xref: /linux/drivers/acpi/acpi_video.c (revision 24bce201d79807b668bf9d9e0aca801c5c0d5f78)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *  video.c - ACPI Video Driver
4  *
5  *  Copyright (C) 2004 Luming Yu <luming.yu@intel.com>
6  *  Copyright (C) 2004 Bruno Ducrot <ducrot@poupinou.org>
7  *  Copyright (C) 2006 Thomas Tuttle <linux-kernel@ttuttle.net>
8  */
9 
10 #define pr_fmt(fmt) "ACPI: video: " fmt
11 
12 #include <linux/kernel.h>
13 #include <linux/module.h>
14 #include <linux/init.h>
15 #include <linux/types.h>
16 #include <linux/list.h>
17 #include <linux/mutex.h>
18 #include <linux/input.h>
19 #include <linux/backlight.h>
20 #include <linux/thermal.h>
21 #include <linux/sort.h>
22 #include <linux/pci.h>
23 #include <linux/pci_ids.h>
24 #include <linux/slab.h>
25 #include <linux/dmi.h>
26 #include <linux/suspend.h>
27 #include <linux/acpi.h>
28 #include <acpi/video.h>
29 #include <linux/uaccess.h>
30 
31 #define ACPI_VIDEO_BUS_NAME		"Video Bus"
32 #define ACPI_VIDEO_DEVICE_NAME		"Video Device"
33 
34 #define MAX_NAME_LEN	20
35 
36 MODULE_AUTHOR("Bruno Ducrot");
37 MODULE_DESCRIPTION("ACPI Video Driver");
38 MODULE_LICENSE("GPL");
39 
40 static bool brightness_switch_enabled = true;
41 module_param(brightness_switch_enabled, bool, 0644);
42 
43 /*
44  * By default, we don't allow duplicate ACPI video bus devices
45  * under the same VGA controller
46  */
47 static bool allow_duplicates;
48 module_param(allow_duplicates, bool, 0644);
49 
50 static int disable_backlight_sysfs_if = -1;
51 module_param(disable_backlight_sysfs_if, int, 0444);
52 
53 #define REPORT_OUTPUT_KEY_EVENTS		0x01
54 #define REPORT_BRIGHTNESS_KEY_EVENTS		0x02
55 static int report_key_events = -1;
56 module_param(report_key_events, int, 0644);
57 MODULE_PARM_DESC(report_key_events,
58 	"0: none, 1: output changes, 2: brightness changes, 3: all");
59 
60 static int hw_changes_brightness = -1;
61 module_param(hw_changes_brightness, int, 0644);
62 MODULE_PARM_DESC(hw_changes_brightness,
63 	"Set this to 1 on buggy hw which changes the brightness itself when "
64 	"a hotkey is pressed: -1: auto, 0: normal 1: hw-changes-brightness");
65 
66 /*
67  * Whether the struct acpi_video_device_attrib::device_id_scheme bit should be
68  * assumed even if not actually set.
69  */
70 static bool device_id_scheme = false;
71 module_param(device_id_scheme, bool, 0444);
72 
73 static int only_lcd = -1;
74 module_param(only_lcd, int, 0444);
75 
76 static bool has_backlight;
77 static int register_count;
78 static DEFINE_MUTEX(register_count_mutex);
79 static DEFINE_MUTEX(video_list_lock);
80 static LIST_HEAD(video_bus_head);
81 static int acpi_video_bus_add(struct acpi_device *device);
82 static int acpi_video_bus_remove(struct acpi_device *device);
83 static void acpi_video_bus_notify(struct acpi_device *device, u32 event);
84 void acpi_video_detect_exit(void);
85 
86 /*
87  * Indices in the _BCL method response: the first two items are special,
88  * the rest are all supported levels.
89  *
90  * See page 575 of the ACPI spec 3.0
91  */
92 enum acpi_video_level_idx {
93 	ACPI_VIDEO_AC_LEVEL,		/* level when machine has full power */
94 	ACPI_VIDEO_BATTERY_LEVEL,	/* level when machine is on batteries */
95 	ACPI_VIDEO_FIRST_LEVEL,		/* actual supported levels begin here */
96 };
97 
98 static const struct acpi_device_id video_device_ids[] = {
99 	{ACPI_VIDEO_HID, 0},
100 	{"", 0},
101 };
102 MODULE_DEVICE_TABLE(acpi, video_device_ids);
103 
104 static struct acpi_driver acpi_video_bus = {
105 	.name = "video",
106 	.class = ACPI_VIDEO_CLASS,
107 	.ids = video_device_ids,
108 	.ops = {
109 		.add = acpi_video_bus_add,
110 		.remove = acpi_video_bus_remove,
111 		.notify = acpi_video_bus_notify,
112 		},
113 };
114 
115 struct acpi_video_bus_flags {
116 	u8 multihead:1;		/* can switch video heads */
117 	u8 rom:1;		/* can retrieve a video rom */
118 	u8 post:1;		/* can configure the head to */
119 	u8 reserved:5;
120 };
121 
122 struct acpi_video_bus_cap {
123 	u8 _DOS:1;		/* Enable/Disable output switching */
124 	u8 _DOD:1;		/* Enumerate all devices attached to display adapter */
125 	u8 _ROM:1;		/* Get ROM Data */
126 	u8 _GPD:1;		/* Get POST Device */
127 	u8 _SPD:1;		/* Set POST Device */
128 	u8 _VPO:1;		/* Video POST Options */
129 	u8 reserved:2;
130 };
131 
132 struct acpi_video_device_attrib {
133 	u32 display_index:4;	/* A zero-based instance of the Display */
134 	u32 display_port_attachment:4;	/* This field differentiates the display type */
135 	u32 display_type:4;	/* Describe the specific type in use */
136 	u32 vendor_specific:4;	/* Chipset Vendor Specific */
137 	u32 bios_can_detect:1;	/* BIOS can detect the device */
138 	u32 depend_on_vga:1;	/* Non-VGA output device whose power is related to
139 				   the VGA device. */
140 	u32 pipe_id:3;		/* For VGA multiple-head devices. */
141 	u32 reserved:10;	/* Must be 0 */
142 
143 	/*
144 	 * The device ID might not actually follow the scheme described by this
145 	 * struct acpi_video_device_attrib. If it does, then this bit
146 	 * device_id_scheme is set; otherwise, other fields should be ignored.
147 	 *
148 	 * (but also see the global flag device_id_scheme)
149 	 */
150 	u32 device_id_scheme:1;
151 };
152 
153 struct acpi_video_enumerated_device {
154 	union {
155 		u32 int_val;
156 		struct acpi_video_device_attrib attrib;
157 	} value;
158 	struct acpi_video_device *bind_info;
159 };
160 
161 struct acpi_video_bus {
162 	struct acpi_device *device;
163 	bool backlight_registered;
164 	u8 dos_setting;
165 	struct acpi_video_enumerated_device *attached_array;
166 	u8 attached_count;
167 	u8 child_count;
168 	struct acpi_video_bus_cap cap;
169 	struct acpi_video_bus_flags flags;
170 	struct list_head video_device_list;
171 	struct mutex device_list_lock;	/* protects video_device_list */
172 	struct list_head entry;
173 	struct input_dev *input;
174 	char phys[32];	/* for input device */
175 	struct notifier_block pm_nb;
176 };
177 
178 struct acpi_video_device_flags {
179 	u8 crt:1;
180 	u8 lcd:1;
181 	u8 tvout:1;
182 	u8 dvi:1;
183 	u8 bios:1;
184 	u8 unknown:1;
185 	u8 notify:1;
186 	u8 reserved:1;
187 };
188 
189 struct acpi_video_device_cap {
190 	u8 _ADR:1;		/* Return the unique ID */
191 	u8 _BCL:1;		/* Query list of brightness control levels supported */
192 	u8 _BCM:1;		/* Set the brightness level */
193 	u8 _BQC:1;		/* Get current brightness level */
194 	u8 _BCQ:1;		/* Some buggy BIOS uses _BCQ instead of _BQC */
195 	u8 _DDC:1;		/* Return the EDID for this device */
196 };
197 
198 struct acpi_video_device {
199 	unsigned long device_id;
200 	struct acpi_video_device_flags flags;
201 	struct acpi_video_device_cap cap;
202 	struct list_head entry;
203 	struct delayed_work switch_brightness_work;
204 	int switch_brightness_event;
205 	struct acpi_video_bus *video;
206 	struct acpi_device *dev;
207 	struct acpi_video_device_brightness *brightness;
208 	struct backlight_device *backlight;
209 	struct thermal_cooling_device *cooling_dev;
210 };
211 
212 static void acpi_video_device_notify(acpi_handle handle, u32 event, void *data);
213 static void acpi_video_device_rebind(struct acpi_video_bus *video);
214 static void acpi_video_device_bind(struct acpi_video_bus *video,
215 				   struct acpi_video_device *device);
216 static int acpi_video_device_enumerate(struct acpi_video_bus *video);
217 static int acpi_video_device_lcd_set_level(struct acpi_video_device *device,
218 			int level);
219 static int acpi_video_device_lcd_get_level_current(
220 			struct acpi_video_device *device,
221 			unsigned long long *level, bool raw);
222 static int acpi_video_get_next_level(struct acpi_video_device *device,
223 				     u32 level_current, u32 event);
224 static void acpi_video_switch_brightness(struct work_struct *work);
225 
226 /* backlight device sysfs support */
227 static int acpi_video_get_brightness(struct backlight_device *bd)
228 {
229 	unsigned long long cur_level;
230 	int i;
231 	struct acpi_video_device *vd = bl_get_data(bd);
232 
233 	if (acpi_video_device_lcd_get_level_current(vd, &cur_level, false))
234 		return -EINVAL;
235 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < vd->brightness->count; i++) {
236 		if (vd->brightness->levels[i] == cur_level)
237 			return i - ACPI_VIDEO_FIRST_LEVEL;
238 	}
239 	return 0;
240 }
241 
242 static int acpi_video_set_brightness(struct backlight_device *bd)
243 {
244 	int request_level = bd->props.brightness + ACPI_VIDEO_FIRST_LEVEL;
245 	struct acpi_video_device *vd = bl_get_data(bd);
246 
247 	cancel_delayed_work(&vd->switch_brightness_work);
248 	return acpi_video_device_lcd_set_level(vd,
249 				vd->brightness->levels[request_level]);
250 }
251 
252 static const struct backlight_ops acpi_backlight_ops = {
253 	.get_brightness = acpi_video_get_brightness,
254 	.update_status  = acpi_video_set_brightness,
255 };
256 
257 /* thermal cooling device callbacks */
258 static int video_get_max_state(struct thermal_cooling_device *cooling_dev,
259 			       unsigned long *state)
260 {
261 	struct acpi_device *device = cooling_dev->devdata;
262 	struct acpi_video_device *video = acpi_driver_data(device);
263 
264 	*state = video->brightness->count - ACPI_VIDEO_FIRST_LEVEL - 1;
265 	return 0;
266 }
267 
268 static int video_get_cur_state(struct thermal_cooling_device *cooling_dev,
269 			       unsigned long *state)
270 {
271 	struct acpi_device *device = cooling_dev->devdata;
272 	struct acpi_video_device *video = acpi_driver_data(device);
273 	unsigned long long level;
274 	int offset;
275 
276 	if (acpi_video_device_lcd_get_level_current(video, &level, false))
277 		return -EINVAL;
278 	for (offset = ACPI_VIDEO_FIRST_LEVEL; offset < video->brightness->count;
279 	     offset++)
280 		if (level == video->brightness->levels[offset]) {
281 			*state = video->brightness->count - offset - 1;
282 			return 0;
283 		}
284 
285 	return -EINVAL;
286 }
287 
288 static int
289 video_set_cur_state(struct thermal_cooling_device *cooling_dev, unsigned long state)
290 {
291 	struct acpi_device *device = cooling_dev->devdata;
292 	struct acpi_video_device *video = acpi_driver_data(device);
293 	int level;
294 
295 	if (state >= video->brightness->count - ACPI_VIDEO_FIRST_LEVEL)
296 		return -EINVAL;
297 
298 	state = video->brightness->count - state;
299 	level = video->brightness->levels[state - 1];
300 	return acpi_video_device_lcd_set_level(video, level);
301 }
302 
303 static const struct thermal_cooling_device_ops video_cooling_ops = {
304 	.get_max_state = video_get_max_state,
305 	.get_cur_state = video_get_cur_state,
306 	.set_cur_state = video_set_cur_state,
307 };
308 
309 /*
310  * --------------------------------------------------------------------------
311  *                             Video Management
312  * --------------------------------------------------------------------------
313  */
314 
315 static int
316 acpi_video_device_lcd_query_levels(acpi_handle handle,
317 				   union acpi_object **levels)
318 {
319 	int status;
320 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
321 	union acpi_object *obj;
322 
323 
324 	*levels = NULL;
325 
326 	status = acpi_evaluate_object(handle, "_BCL", NULL, &buffer);
327 	if (ACPI_FAILURE(status))
328 		return status;
329 	obj = (union acpi_object *)buffer.pointer;
330 	if (!obj || (obj->type != ACPI_TYPE_PACKAGE)) {
331 		acpi_handle_info(handle, "Invalid _BCL data\n");
332 		status = -EFAULT;
333 		goto err;
334 	}
335 
336 	*levels = obj;
337 
338 	return 0;
339 
340 err:
341 	kfree(buffer.pointer);
342 
343 	return status;
344 }
345 
346 static int
347 acpi_video_device_lcd_set_level(struct acpi_video_device *device, int level)
348 {
349 	int status;
350 	int state;
351 
352 	status = acpi_execute_simple_method(device->dev->handle,
353 					    "_BCM", level);
354 	if (ACPI_FAILURE(status)) {
355 		acpi_handle_info(device->dev->handle, "_BCM evaluation failed\n");
356 		return -EIO;
357 	}
358 
359 	device->brightness->curr = level;
360 	for (state = ACPI_VIDEO_FIRST_LEVEL; state < device->brightness->count;
361 	     state++)
362 		if (level == device->brightness->levels[state]) {
363 			if (device->backlight)
364 				device->backlight->props.brightness =
365 					state - ACPI_VIDEO_FIRST_LEVEL;
366 			return 0;
367 		}
368 
369 	acpi_handle_info(device->dev->handle, "Current brightness invalid\n");
370 	return -EINVAL;
371 }
372 
373 /*
374  * For some buggy _BQC methods, we need to add a constant value to
375  * the _BQC return value to get the actual current brightness level
376  */
377 
378 static int bqc_offset_aml_bug_workaround;
379 static int video_set_bqc_offset(const struct dmi_system_id *d)
380 {
381 	bqc_offset_aml_bug_workaround = 9;
382 	return 0;
383 }
384 
385 static int video_disable_backlight_sysfs_if(
386 	const struct dmi_system_id *d)
387 {
388 	if (disable_backlight_sysfs_if == -1)
389 		disable_backlight_sysfs_if = 1;
390 	return 0;
391 }
392 
393 static int video_set_device_id_scheme(const struct dmi_system_id *d)
394 {
395 	device_id_scheme = true;
396 	return 0;
397 }
398 
399 static int video_enable_only_lcd(const struct dmi_system_id *d)
400 {
401 	only_lcd = true;
402 	return 0;
403 }
404 
405 static int video_set_report_key_events(const struct dmi_system_id *id)
406 {
407 	if (report_key_events == -1)
408 		report_key_events = (uintptr_t)id->driver_data;
409 	return 0;
410 }
411 
412 static int video_hw_changes_brightness(
413 	const struct dmi_system_id *d)
414 {
415 	if (hw_changes_brightness == -1)
416 		hw_changes_brightness = 1;
417 	return 0;
418 }
419 
420 static const struct dmi_system_id video_dmi_table[] = {
421 	/*
422 	 * Broken _BQC workaround http://bugzilla.kernel.org/show_bug.cgi?id=13121
423 	 */
424 	{
425 	 .callback = video_set_bqc_offset,
426 	 .ident = "Acer Aspire 5720",
427 	 .matches = {
428 		DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
429 		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5720"),
430 		},
431 	},
432 	{
433 	 .callback = video_set_bqc_offset,
434 	 .ident = "Acer Aspire 5710Z",
435 	 .matches = {
436 		DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
437 		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5710Z"),
438 		},
439 	},
440 	{
441 	 .callback = video_set_bqc_offset,
442 	 .ident = "eMachines E510",
443 	 .matches = {
444 		DMI_MATCH(DMI_BOARD_VENDOR, "EMACHINES"),
445 		DMI_MATCH(DMI_PRODUCT_NAME, "eMachines E510"),
446 		},
447 	},
448 	{
449 	 .callback = video_set_bqc_offset,
450 	 .ident = "Acer Aspire 5315",
451 	 .matches = {
452 		DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
453 		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5315"),
454 		},
455 	},
456 	{
457 	 .callback = video_set_bqc_offset,
458 	 .ident = "Acer Aspire 7720",
459 	 .matches = {
460 		DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
461 		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 7720"),
462 		},
463 	},
464 
465 	/*
466 	 * Some machines have a broken acpi-video interface for brightness
467 	 * control, but still need an acpi_video_device_lcd_set_level() call
468 	 * on resume to turn the backlight power on.  We Enable backlight
469 	 * control on these systems, but do not register a backlight sysfs
470 	 * as brightness control does not work.
471 	 */
472 	{
473 	 /* https://bugzilla.kernel.org/show_bug.cgi?id=21012 */
474 	 .callback = video_disable_backlight_sysfs_if,
475 	 .ident = "Toshiba Portege R700",
476 	 .matches = {
477 		DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
478 		DMI_MATCH(DMI_PRODUCT_NAME, "PORTEGE R700"),
479 		},
480 	},
481 	{
482 	 /* https://bugs.freedesktop.org/show_bug.cgi?id=82634 */
483 	 .callback = video_disable_backlight_sysfs_if,
484 	 .ident = "Toshiba Portege R830",
485 	 .matches = {
486 		DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
487 		DMI_MATCH(DMI_PRODUCT_NAME, "PORTEGE R830"),
488 		},
489 	},
490 	{
491 	 /* https://bugzilla.kernel.org/show_bug.cgi?id=21012 */
492 	 .callback = video_disable_backlight_sysfs_if,
493 	 .ident = "Toshiba Satellite R830",
494 	 .matches = {
495 		DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
496 		DMI_MATCH(DMI_PRODUCT_NAME, "SATELLITE R830"),
497 		},
498 	},
499 	/*
500 	 * Some machine's _DOD IDs don't have bit 31(Device ID Scheme) set
501 	 * but the IDs actually follow the Device ID Scheme.
502 	 */
503 	{
504 	 /* https://bugzilla.kernel.org/show_bug.cgi?id=104121 */
505 	 .callback = video_set_device_id_scheme,
506 	 .ident = "ESPRIMO Mobile M9410",
507 	 .matches = {
508 		DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU SIEMENS"),
509 		DMI_MATCH(DMI_PRODUCT_NAME, "ESPRIMO Mobile M9410"),
510 		},
511 	},
512 	/*
513 	 * Some machines have multiple video output devices, but only the one
514 	 * that is the type of LCD can do the backlight control so we should not
515 	 * register backlight interface for other video output devices.
516 	 */
517 	{
518 	 /* https://bugzilla.kernel.org/show_bug.cgi?id=104121 */
519 	 .callback = video_enable_only_lcd,
520 	 .ident = "ESPRIMO Mobile M9410",
521 	 .matches = {
522 		DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU SIEMENS"),
523 		DMI_MATCH(DMI_PRODUCT_NAME, "ESPRIMO Mobile M9410"),
524 		},
525 	},
526 	/*
527 	 * Some machines report wrong key events on the acpi-bus, suppress
528 	 * key event reporting on these.  Note this is only intended to work
529 	 * around events which are plain wrong. In some cases we get double
530 	 * events, in this case acpi-video is considered the canonical source
531 	 * and the events from the other source should be filtered. E.g.
532 	 * by calling acpi_video_handles_brightness_key_presses() from the
533 	 * vendor acpi/wmi driver or by using /lib/udev/hwdb.d/60-keyboard.hwdb
534 	 */
535 	{
536 	 .callback = video_set_report_key_events,
537 	 .driver_data = (void *)((uintptr_t)REPORT_OUTPUT_KEY_EVENTS),
538 	 .ident = "Dell Vostro V131",
539 	 .matches = {
540 		DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
541 		DMI_MATCH(DMI_PRODUCT_NAME, "Vostro V131"),
542 		},
543 	},
544 	{
545 	 .callback = video_set_report_key_events,
546 	 .driver_data = (void *)((uintptr_t)REPORT_BRIGHTNESS_KEY_EVENTS),
547 	 .ident = "Dell Vostro 3350",
548 	 .matches = {
549 		DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
550 		DMI_MATCH(DMI_PRODUCT_NAME, "Vostro 3350"),
551 		},
552 	},
553 	/*
554 	 * Some machines change the brightness themselves when a brightness
555 	 * hotkey gets pressed, despite us telling them not to. In this case
556 	 * acpi_video_device_notify() should only call backlight_force_update(
557 	 * BACKLIGHT_UPDATE_HOTKEY) and not do anything else.
558 	 */
559 	{
560 	 /* https://bugzilla.kernel.org/show_bug.cgi?id=204077 */
561 	 .callback = video_hw_changes_brightness,
562 	 .ident = "Packard Bell EasyNote MZ35",
563 	 .matches = {
564 		DMI_MATCH(DMI_SYS_VENDOR, "Packard Bell"),
565 		DMI_MATCH(DMI_PRODUCT_NAME, "EasyNote MZ35"),
566 		},
567 	},
568 	{}
569 };
570 
571 static unsigned long long
572 acpi_video_bqc_value_to_level(struct acpi_video_device *device,
573 			      unsigned long long bqc_value)
574 {
575 	unsigned long long level;
576 
577 	if (device->brightness->flags._BQC_use_index) {
578 		/*
579 		 * _BQC returns an index that doesn't account for the first 2
580 		 * items with special meaning (see enum acpi_video_level_idx),
581 		 * so we need to compensate for that by offsetting ourselves
582 		 */
583 		if (device->brightness->flags._BCL_reversed)
584 			bqc_value = device->brightness->count -
585 				ACPI_VIDEO_FIRST_LEVEL - 1 - bqc_value;
586 
587 		level = device->brightness->levels[bqc_value +
588 						   ACPI_VIDEO_FIRST_LEVEL];
589 	} else {
590 		level = bqc_value;
591 	}
592 
593 	level += bqc_offset_aml_bug_workaround;
594 
595 	return level;
596 }
597 
598 static int
599 acpi_video_device_lcd_get_level_current(struct acpi_video_device *device,
600 					unsigned long long *level, bool raw)
601 {
602 	acpi_status status = AE_OK;
603 	int i;
604 
605 	if (device->cap._BQC || device->cap._BCQ) {
606 		char *buf = device->cap._BQC ? "_BQC" : "_BCQ";
607 
608 		status = acpi_evaluate_integer(device->dev->handle, buf,
609 						NULL, level);
610 		if (ACPI_SUCCESS(status)) {
611 			if (raw) {
612 				/*
613 				 * Caller has indicated he wants the raw
614 				 * value returned by _BQC, so don't furtherly
615 				 * mess with the value.
616 				 */
617 				return 0;
618 			}
619 
620 			*level = acpi_video_bqc_value_to_level(device, *level);
621 
622 			for (i = ACPI_VIDEO_FIRST_LEVEL;
623 			     i < device->brightness->count; i++)
624 				if (device->brightness->levels[i] == *level) {
625 					device->brightness->curr = *level;
626 					return 0;
627 				}
628 			/*
629 			 * BQC returned an invalid level.
630 			 * Stop using it.
631 			 */
632 			acpi_handle_info(device->dev->handle,
633 					 "%s returned an invalid level", buf);
634 			device->cap._BQC = device->cap._BCQ = 0;
635 		} else {
636 			/*
637 			 * Fixme:
638 			 * should we return an error or ignore this failure?
639 			 * dev->brightness->curr is a cached value which stores
640 			 * the correct current backlight level in most cases.
641 			 * ACPI video backlight still works w/ buggy _BQC.
642 			 * http://bugzilla.kernel.org/show_bug.cgi?id=12233
643 			 */
644 			acpi_handle_info(device->dev->handle,
645 					 "%s evaluation failed", buf);
646 			device->cap._BQC = device->cap._BCQ = 0;
647 		}
648 	}
649 
650 	*level = device->brightness->curr;
651 	return 0;
652 }
653 
654 static int
655 acpi_video_device_EDID(struct acpi_video_device *device,
656 		       union acpi_object **edid, ssize_t length)
657 {
658 	int status;
659 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
660 	union acpi_object *obj;
661 	union acpi_object arg0 = { ACPI_TYPE_INTEGER };
662 	struct acpi_object_list args = { 1, &arg0 };
663 
664 
665 	*edid = NULL;
666 
667 	if (!device)
668 		return -ENODEV;
669 	if (length == 128)
670 		arg0.integer.value = 1;
671 	else if (length == 256)
672 		arg0.integer.value = 2;
673 	else
674 		return -EINVAL;
675 
676 	status = acpi_evaluate_object(device->dev->handle, "_DDC", &args, &buffer);
677 	if (ACPI_FAILURE(status))
678 		return -ENODEV;
679 
680 	obj = buffer.pointer;
681 
682 	if (obj && obj->type == ACPI_TYPE_BUFFER)
683 		*edid = obj;
684 	else {
685 		acpi_handle_info(device->dev->handle, "Invalid _DDC data\n");
686 		status = -EFAULT;
687 		kfree(obj);
688 	}
689 
690 	return status;
691 }
692 
693 /* bus */
694 
695 /*
696  *  Arg:
697  *	video		: video bus device pointer
698  *	bios_flag	:
699  *		0.	The system BIOS should NOT automatically switch(toggle)
700  *			the active display output.
701  *		1.	The system BIOS should automatically switch (toggle) the
702  *			active display output. No switch event.
703  *		2.	The _DGS value should be locked.
704  *		3.	The system BIOS should not automatically switch (toggle) the
705  *			active display output, but instead generate the display switch
706  *			event notify code.
707  *	lcd_flag	:
708  *		0.	The system BIOS should automatically control the brightness level
709  *			of the LCD when:
710  *			- the power changes from AC to DC (ACPI appendix B)
711  *			- a brightness hotkey gets pressed (implied by Win7/8 backlight docs)
712  *		1.	The system BIOS should NOT automatically control the brightness
713  *			level of the LCD when:
714  *			- the power changes from AC to DC (ACPI appendix B)
715  *			- a brightness hotkey gets pressed (implied by Win7/8 backlight docs)
716  *  Return Value:
717  *		-EINVAL	wrong arg.
718  */
719 
720 static int
721 acpi_video_bus_DOS(struct acpi_video_bus *video, int bios_flag, int lcd_flag)
722 {
723 	acpi_status status;
724 
725 	if (!video->cap._DOS)
726 		return 0;
727 
728 	if (bios_flag < 0 || bios_flag > 3 || lcd_flag < 0 || lcd_flag > 1)
729 		return -EINVAL;
730 	video->dos_setting = (lcd_flag << 2) | bios_flag;
731 	status = acpi_execute_simple_method(video->device->handle, "_DOS",
732 					    (lcd_flag << 2) | bios_flag);
733 	if (ACPI_FAILURE(status))
734 		return -EIO;
735 
736 	return 0;
737 }
738 
739 /*
740  * Simple comparison function used to sort backlight levels.
741  */
742 
743 static int
744 acpi_video_cmp_level(const void *a, const void *b)
745 {
746 	return *(int *)a - *(int *)b;
747 }
748 
749 /*
750  * Decides if _BQC/_BCQ for this system is usable
751  *
752  * We do this by changing the level first and then read out the current
753  * brightness level, if the value does not match, find out if it is using
754  * index. If not, clear the _BQC/_BCQ capability.
755  */
756 static int acpi_video_bqc_quirk(struct acpi_video_device *device,
757 				int max_level, int current_level)
758 {
759 	struct acpi_video_device_brightness *br = device->brightness;
760 	int result;
761 	unsigned long long level;
762 	int test_level;
763 
764 	/* don't mess with existing known broken systems */
765 	if (bqc_offset_aml_bug_workaround)
766 		return 0;
767 
768 	/*
769 	 * Some systems always report current brightness level as maximum
770 	 * through _BQC, we need to test another value for them. However,
771 	 * there is a subtlety:
772 	 *
773 	 * If the _BCL package ordering is descending, the first level
774 	 * (br->levels[2]) is likely to be 0, and if the number of levels
775 	 * matches the number of steps, we might confuse a returned level to
776 	 * mean the index.
777 	 *
778 	 * For example:
779 	 *
780 	 *     current_level = max_level = 100
781 	 *     test_level = 0
782 	 *     returned level = 100
783 	 *
784 	 * In this case 100 means the level, not the index, and _BCM failed.
785 	 * Still, if the _BCL package ordering is descending, the index of
786 	 * level 0 is also 100, so we assume _BQC is indexed, when it's not.
787 	 *
788 	 * This causes all _BQC calls to return bogus values causing weird
789 	 * behavior from the user's perspective.  For example:
790 	 *
791 	 * xbacklight -set 10; xbacklight -set 20;
792 	 *
793 	 * would flash to 90% and then slowly down to the desired level (20).
794 	 *
795 	 * The solution is simple; test anything other than the first level
796 	 * (e.g. 1).
797 	 */
798 	test_level = current_level == max_level
799 		? br->levels[ACPI_VIDEO_FIRST_LEVEL + 1]
800 		: max_level;
801 
802 	result = acpi_video_device_lcd_set_level(device, test_level);
803 	if (result)
804 		return result;
805 
806 	result = acpi_video_device_lcd_get_level_current(device, &level, true);
807 	if (result)
808 		return result;
809 
810 	if (level != test_level) {
811 		/* buggy _BQC found, need to find out if it uses index */
812 		if (level < br->count) {
813 			if (br->flags._BCL_reversed)
814 				level = br->count - ACPI_VIDEO_FIRST_LEVEL - 1 - level;
815 			if (br->levels[level + ACPI_VIDEO_FIRST_LEVEL] == test_level)
816 				br->flags._BQC_use_index = 1;
817 		}
818 
819 		if (!br->flags._BQC_use_index)
820 			device->cap._BQC = device->cap._BCQ = 0;
821 	}
822 
823 	return 0;
824 }
825 
826 int acpi_video_get_levels(struct acpi_device *device,
827 			  struct acpi_video_device_brightness **dev_br,
828 			  int *pmax_level)
829 {
830 	union acpi_object *obj = NULL;
831 	int i, max_level = 0, count = 0, level_ac_battery = 0;
832 	union acpi_object *o;
833 	struct acpi_video_device_brightness *br = NULL;
834 	int result = 0;
835 	u32 value;
836 
837 	if (ACPI_FAILURE(acpi_video_device_lcd_query_levels(device->handle, &obj))) {
838 		acpi_handle_debug(device->handle,
839 				  "Could not query available LCD brightness level\n");
840 		result = -ENODEV;
841 		goto out;
842 	}
843 
844 	if (obj->package.count < ACPI_VIDEO_FIRST_LEVEL) {
845 		result = -EINVAL;
846 		goto out;
847 	}
848 
849 	br = kzalloc(sizeof(*br), GFP_KERNEL);
850 	if (!br) {
851 		result = -ENOMEM;
852 		goto out;
853 	}
854 
855 	/*
856 	 * Note that we have to reserve 2 extra items (ACPI_VIDEO_FIRST_LEVEL),
857 	 * in order to account for buggy BIOS which don't export the first two
858 	 * special levels (see below)
859 	 */
860 	br->levels = kmalloc_array(obj->package.count + ACPI_VIDEO_FIRST_LEVEL,
861 				   sizeof(*br->levels),
862 				   GFP_KERNEL);
863 	if (!br->levels) {
864 		result = -ENOMEM;
865 		goto out_free;
866 	}
867 
868 	for (i = 0; i < obj->package.count; i++) {
869 		o = (union acpi_object *)&obj->package.elements[i];
870 		if (o->type != ACPI_TYPE_INTEGER) {
871 			acpi_handle_info(device->handle, "Invalid data\n");
872 			continue;
873 		}
874 		value = (u32) o->integer.value;
875 		/* Skip duplicate entries */
876 		if (count > ACPI_VIDEO_FIRST_LEVEL
877 		    && br->levels[count - 1] == value)
878 			continue;
879 
880 		br->levels[count] = value;
881 
882 		if (br->levels[count] > max_level)
883 			max_level = br->levels[count];
884 		count++;
885 	}
886 
887 	/*
888 	 * some buggy BIOS don't export the levels
889 	 * when machine is on AC/Battery in _BCL package.
890 	 * In this case, the first two elements in _BCL packages
891 	 * are also supported brightness levels that OS should take care of.
892 	 */
893 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < count; i++) {
894 		if (br->levels[i] == br->levels[ACPI_VIDEO_AC_LEVEL])
895 			level_ac_battery++;
896 		if (br->levels[i] == br->levels[ACPI_VIDEO_BATTERY_LEVEL])
897 			level_ac_battery++;
898 	}
899 
900 	if (level_ac_battery < ACPI_VIDEO_FIRST_LEVEL) {
901 		level_ac_battery = ACPI_VIDEO_FIRST_LEVEL - level_ac_battery;
902 		br->flags._BCL_no_ac_battery_levels = 1;
903 		for (i = (count - 1 + level_ac_battery);
904 		     i >= ACPI_VIDEO_FIRST_LEVEL; i--)
905 			br->levels[i] = br->levels[i - level_ac_battery];
906 		count += level_ac_battery;
907 	} else if (level_ac_battery > ACPI_VIDEO_FIRST_LEVEL)
908 		acpi_handle_info(device->handle,
909 				 "Too many duplicates in _BCL package");
910 
911 	/* Check if the _BCL package is in a reversed order */
912 	if (max_level == br->levels[ACPI_VIDEO_FIRST_LEVEL]) {
913 		br->flags._BCL_reversed = 1;
914 		sort(&br->levels[ACPI_VIDEO_FIRST_LEVEL],
915 		     count - ACPI_VIDEO_FIRST_LEVEL,
916 		     sizeof(br->levels[ACPI_VIDEO_FIRST_LEVEL]),
917 		     acpi_video_cmp_level, NULL);
918 	} else if (max_level != br->levels[count - 1])
919 		acpi_handle_info(device->handle,
920 				 "Found unordered _BCL package");
921 
922 	br->count = count;
923 	*dev_br = br;
924 	if (pmax_level)
925 		*pmax_level = max_level;
926 
927 out:
928 	kfree(obj);
929 	return result;
930 out_free:
931 	kfree(br);
932 	goto out;
933 }
934 EXPORT_SYMBOL(acpi_video_get_levels);
935 
936 /*
937  *  Arg:
938  *	device	: video output device (LCD, CRT, ..)
939  *
940  *  Return Value:
941  *	Maximum brightness level
942  *
943  *  Allocate and initialize device->brightness.
944  */
945 
946 static int
947 acpi_video_init_brightness(struct acpi_video_device *device)
948 {
949 	int i, max_level = 0;
950 	unsigned long long level, level_old;
951 	struct acpi_video_device_brightness *br = NULL;
952 	int result;
953 
954 	result = acpi_video_get_levels(device->dev, &br, &max_level);
955 	if (result)
956 		return result;
957 	device->brightness = br;
958 
959 	/* _BQC uses INDEX while _BCL uses VALUE in some laptops */
960 	br->curr = level = max_level;
961 
962 	if (!device->cap._BQC)
963 		goto set_level;
964 
965 	result = acpi_video_device_lcd_get_level_current(device,
966 							 &level_old, true);
967 	if (result)
968 		goto out_free_levels;
969 
970 	result = acpi_video_bqc_quirk(device, max_level, level_old);
971 	if (result)
972 		goto out_free_levels;
973 	/*
974 	 * cap._BQC may get cleared due to _BQC is found to be broken
975 	 * in acpi_video_bqc_quirk, so check again here.
976 	 */
977 	if (!device->cap._BQC)
978 		goto set_level;
979 
980 	level = acpi_video_bqc_value_to_level(device, level_old);
981 	/*
982 	 * On some buggy laptops, _BQC returns an uninitialized
983 	 * value when invoked for the first time, i.e.
984 	 * level_old is invalid (no matter whether it's a level
985 	 * or an index). Set the backlight to max_level in this case.
986 	 */
987 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < br->count; i++)
988 		if (level == br->levels[i])
989 			break;
990 	if (i == br->count || !level)
991 		level = max_level;
992 
993 set_level:
994 	result = acpi_video_device_lcd_set_level(device, level);
995 	if (result)
996 		goto out_free_levels;
997 
998 	acpi_handle_debug(device->dev->handle, "found %d brightness levels\n",
999 			  br->count - ACPI_VIDEO_FIRST_LEVEL);
1000 
1001 	return 0;
1002 
1003 out_free_levels:
1004 	kfree(br->levels);
1005 	kfree(br);
1006 	device->brightness = NULL;
1007 	return result;
1008 }
1009 
1010 /*
1011  *  Arg:
1012  *	device	: video output device (LCD, CRT, ..)
1013  *
1014  *  Return Value:
1015  *	None
1016  *
1017  *  Find out all required AML methods defined under the output
1018  *  device.
1019  */
1020 
1021 static void acpi_video_device_find_cap(struct acpi_video_device *device)
1022 {
1023 	if (acpi_has_method(device->dev->handle, "_ADR"))
1024 		device->cap._ADR = 1;
1025 	if (acpi_has_method(device->dev->handle, "_BCL"))
1026 		device->cap._BCL = 1;
1027 	if (acpi_has_method(device->dev->handle, "_BCM"))
1028 		device->cap._BCM = 1;
1029 	if (acpi_has_method(device->dev->handle, "_BQC")) {
1030 		device->cap._BQC = 1;
1031 	} else if (acpi_has_method(device->dev->handle, "_BCQ")) {
1032 		acpi_handle_info(device->dev->handle,
1033 				 "_BCQ is used instead of _BQC\n");
1034 		device->cap._BCQ = 1;
1035 	}
1036 
1037 	if (acpi_has_method(device->dev->handle, "_DDC"))
1038 		device->cap._DDC = 1;
1039 }
1040 
1041 /*
1042  *  Arg:
1043  *	device	: video output device (VGA)
1044  *
1045  *  Return Value:
1046  *	None
1047  *
1048  *  Find out all required AML methods defined under the video bus device.
1049  */
1050 
1051 static void acpi_video_bus_find_cap(struct acpi_video_bus *video)
1052 {
1053 	if (acpi_has_method(video->device->handle, "_DOS"))
1054 		video->cap._DOS = 1;
1055 	if (acpi_has_method(video->device->handle, "_DOD"))
1056 		video->cap._DOD = 1;
1057 	if (acpi_has_method(video->device->handle, "_ROM"))
1058 		video->cap._ROM = 1;
1059 	if (acpi_has_method(video->device->handle, "_GPD"))
1060 		video->cap._GPD = 1;
1061 	if (acpi_has_method(video->device->handle, "_SPD"))
1062 		video->cap._SPD = 1;
1063 	if (acpi_has_method(video->device->handle, "_VPO"))
1064 		video->cap._VPO = 1;
1065 }
1066 
1067 /*
1068  * Check whether the video bus device has required AML method to
1069  * support the desired features
1070  */
1071 
1072 static int acpi_video_bus_check(struct acpi_video_bus *video)
1073 {
1074 	acpi_status status = -ENOENT;
1075 	struct pci_dev *dev;
1076 
1077 	if (!video)
1078 		return -EINVAL;
1079 
1080 	dev = acpi_get_pci_dev(video->device->handle);
1081 	if (!dev)
1082 		return -ENODEV;
1083 	pci_dev_put(dev);
1084 
1085 	/*
1086 	 * Since there is no HID, CID and so on for VGA driver, we have
1087 	 * to check well known required nodes.
1088 	 */
1089 
1090 	/* Does this device support video switching? */
1091 	if (video->cap._DOS || video->cap._DOD) {
1092 		if (!video->cap._DOS) {
1093 			pr_info(FW_BUG "ACPI(%s) defines _DOD but not _DOS\n",
1094 				acpi_device_bid(video->device));
1095 		}
1096 		video->flags.multihead = 1;
1097 		status = 0;
1098 	}
1099 
1100 	/* Does this device support retrieving a video ROM? */
1101 	if (video->cap._ROM) {
1102 		video->flags.rom = 1;
1103 		status = 0;
1104 	}
1105 
1106 	/* Does this device support configuring which video device to POST? */
1107 	if (video->cap._GPD && video->cap._SPD && video->cap._VPO) {
1108 		video->flags.post = 1;
1109 		status = 0;
1110 	}
1111 
1112 	return status;
1113 }
1114 
1115 /*
1116  * --------------------------------------------------------------------------
1117  *                               Driver Interface
1118  * --------------------------------------------------------------------------
1119  */
1120 
1121 /* device interface */
1122 static struct acpi_video_device_attrib *
1123 acpi_video_get_device_attr(struct acpi_video_bus *video, unsigned long device_id)
1124 {
1125 	struct acpi_video_enumerated_device *ids;
1126 	int i;
1127 
1128 	for (i = 0; i < video->attached_count; i++) {
1129 		ids = &video->attached_array[i];
1130 		if ((ids->value.int_val & 0xffff) == device_id)
1131 			return &ids->value.attrib;
1132 	}
1133 
1134 	return NULL;
1135 }
1136 
1137 static int
1138 acpi_video_get_device_type(struct acpi_video_bus *video,
1139 			   unsigned long device_id)
1140 {
1141 	struct acpi_video_enumerated_device *ids;
1142 	int i;
1143 
1144 	for (i = 0; i < video->attached_count; i++) {
1145 		ids = &video->attached_array[i];
1146 		if ((ids->value.int_val & 0xffff) == device_id)
1147 			return ids->value.int_val;
1148 	}
1149 
1150 	return 0;
1151 }
1152 
1153 static int
1154 acpi_video_bus_get_one_device(struct acpi_device *device,
1155 			      struct acpi_video_bus *video)
1156 {
1157 	unsigned long long device_id;
1158 	int status, device_type;
1159 	struct acpi_video_device *data;
1160 	struct acpi_video_device_attrib *attribute;
1161 
1162 	status =
1163 	    acpi_evaluate_integer(device->handle, "_ADR", NULL, &device_id);
1164 	/* Some device omits _ADR, we skip them instead of fail */
1165 	if (ACPI_FAILURE(status))
1166 		return 0;
1167 
1168 	data = kzalloc(sizeof(struct acpi_video_device), GFP_KERNEL);
1169 	if (!data)
1170 		return -ENOMEM;
1171 
1172 	strcpy(acpi_device_name(device), ACPI_VIDEO_DEVICE_NAME);
1173 	strcpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
1174 	device->driver_data = data;
1175 
1176 	data->device_id = device_id;
1177 	data->video = video;
1178 	data->dev = device;
1179 	INIT_DELAYED_WORK(&data->switch_brightness_work,
1180 			  acpi_video_switch_brightness);
1181 
1182 	attribute = acpi_video_get_device_attr(video, device_id);
1183 
1184 	if (attribute && (attribute->device_id_scheme || device_id_scheme)) {
1185 		switch (attribute->display_type) {
1186 		case ACPI_VIDEO_DISPLAY_CRT:
1187 			data->flags.crt = 1;
1188 			break;
1189 		case ACPI_VIDEO_DISPLAY_TV:
1190 			data->flags.tvout = 1;
1191 			break;
1192 		case ACPI_VIDEO_DISPLAY_DVI:
1193 			data->flags.dvi = 1;
1194 			break;
1195 		case ACPI_VIDEO_DISPLAY_LCD:
1196 			data->flags.lcd = 1;
1197 			break;
1198 		default:
1199 			data->flags.unknown = 1;
1200 			break;
1201 		}
1202 		if (attribute->bios_can_detect)
1203 			data->flags.bios = 1;
1204 	} else {
1205 		/* Check for legacy IDs */
1206 		device_type = acpi_video_get_device_type(video, device_id);
1207 		/* Ignore bits 16 and 18-20 */
1208 		switch (device_type & 0xffe2ffff) {
1209 		case ACPI_VIDEO_DISPLAY_LEGACY_MONITOR:
1210 			data->flags.crt = 1;
1211 			break;
1212 		case ACPI_VIDEO_DISPLAY_LEGACY_PANEL:
1213 			data->flags.lcd = 1;
1214 			break;
1215 		case ACPI_VIDEO_DISPLAY_LEGACY_TV:
1216 			data->flags.tvout = 1;
1217 			break;
1218 		default:
1219 			data->flags.unknown = 1;
1220 		}
1221 	}
1222 
1223 	acpi_video_device_bind(video, data);
1224 	acpi_video_device_find_cap(data);
1225 
1226 	if (data->cap._BCM && data->cap._BCL)
1227 		has_backlight = true;
1228 
1229 	mutex_lock(&video->device_list_lock);
1230 	list_add_tail(&data->entry, &video->video_device_list);
1231 	mutex_unlock(&video->device_list_lock);
1232 
1233 	return status;
1234 }
1235 
1236 /*
1237  *  Arg:
1238  *	video	: video bus device
1239  *
1240  *  Return:
1241  *	none
1242  *
1243  *  Enumerate the video device list of the video bus,
1244  *  bind the ids with the corresponding video devices
1245  *  under the video bus.
1246  */
1247 
1248 static void acpi_video_device_rebind(struct acpi_video_bus *video)
1249 {
1250 	struct acpi_video_device *dev;
1251 
1252 	mutex_lock(&video->device_list_lock);
1253 
1254 	list_for_each_entry(dev, &video->video_device_list, entry)
1255 		acpi_video_device_bind(video, dev);
1256 
1257 	mutex_unlock(&video->device_list_lock);
1258 }
1259 
1260 /*
1261  *  Arg:
1262  *	video	: video bus device
1263  *	device	: video output device under the video
1264  *		bus
1265  *
1266  *  Return:
1267  *	none
1268  *
1269  *  Bind the ids with the corresponding video devices
1270  *  under the video bus.
1271  */
1272 
1273 static void
1274 acpi_video_device_bind(struct acpi_video_bus *video,
1275 		       struct acpi_video_device *device)
1276 {
1277 	struct acpi_video_enumerated_device *ids;
1278 	int i;
1279 
1280 	for (i = 0; i < video->attached_count; i++) {
1281 		ids = &video->attached_array[i];
1282 		if (device->device_id == (ids->value.int_val & 0xffff)) {
1283 			ids->bind_info = device;
1284 			acpi_handle_debug(video->device->handle, "%s: %d\n",
1285 					  __func__, i);
1286 		}
1287 	}
1288 }
1289 
1290 static bool acpi_video_device_in_dod(struct acpi_video_device *device)
1291 {
1292 	struct acpi_video_bus *video = device->video;
1293 	int i;
1294 
1295 	/*
1296 	 * If we have a broken _DOD or we have more than 8 output devices
1297 	 * under the graphics controller node that we can't proper deal with
1298 	 * in the operation region code currently, no need to test.
1299 	 */
1300 	if (!video->attached_count || video->child_count > 8)
1301 		return true;
1302 
1303 	for (i = 0; i < video->attached_count; i++) {
1304 		if ((video->attached_array[i].value.int_val & 0xfff) ==
1305 		    (device->device_id & 0xfff))
1306 			return true;
1307 	}
1308 
1309 	return false;
1310 }
1311 
1312 /*
1313  *  Arg:
1314  *	video	: video bus device
1315  *
1316  *  Return:
1317  *	< 0	: error
1318  *
1319  *  Call _DOD to enumerate all devices attached to display adapter
1320  *
1321  */
1322 
1323 static int acpi_video_device_enumerate(struct acpi_video_bus *video)
1324 {
1325 	int status;
1326 	int count;
1327 	int i;
1328 	struct acpi_video_enumerated_device *active_list;
1329 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
1330 	union acpi_object *dod = NULL;
1331 	union acpi_object *obj;
1332 
1333 	if (!video->cap._DOD)
1334 		return AE_NOT_EXIST;
1335 
1336 	status = acpi_evaluate_object(video->device->handle, "_DOD", NULL, &buffer);
1337 	if (ACPI_FAILURE(status)) {
1338 		acpi_handle_info(video->device->handle,
1339 				 "_DOD evaluation failed: %s\n",
1340 				 acpi_format_exception(status));
1341 		return status;
1342 	}
1343 
1344 	dod = buffer.pointer;
1345 	if (!dod || (dod->type != ACPI_TYPE_PACKAGE)) {
1346 		acpi_handle_info(video->device->handle, "Invalid _DOD data\n");
1347 		status = -EFAULT;
1348 		goto out;
1349 	}
1350 
1351 	acpi_handle_debug(video->device->handle, "Found %d video heads in _DOD\n",
1352 			  dod->package.count);
1353 
1354 	active_list = kcalloc(1 + dod->package.count,
1355 			      sizeof(struct acpi_video_enumerated_device),
1356 			      GFP_KERNEL);
1357 	if (!active_list) {
1358 		status = -ENOMEM;
1359 		goto out;
1360 	}
1361 
1362 	count = 0;
1363 	for (i = 0; i < dod->package.count; i++) {
1364 		obj = &dod->package.elements[i];
1365 
1366 		if (obj->type != ACPI_TYPE_INTEGER) {
1367 			acpi_handle_info(video->device->handle,
1368 					 "Invalid _DOD data in element %d\n", i);
1369 			continue;
1370 		}
1371 
1372 		active_list[count].value.int_val = obj->integer.value;
1373 		active_list[count].bind_info = NULL;
1374 
1375 		acpi_handle_debug(video->device->handle,
1376 				  "_DOD element[%d] = %d\n", i,
1377 				  (int)obj->integer.value);
1378 
1379 		count++;
1380 	}
1381 
1382 	kfree(video->attached_array);
1383 
1384 	video->attached_array = active_list;
1385 	video->attached_count = count;
1386 
1387 out:
1388 	kfree(buffer.pointer);
1389 	return status;
1390 }
1391 
1392 static int
1393 acpi_video_get_next_level(struct acpi_video_device *device,
1394 			  u32 level_current, u32 event)
1395 {
1396 	int min, max, min_above, max_below, i, l, delta = 255;
1397 	max = max_below = 0;
1398 	min = min_above = 255;
1399 	/* Find closest level to level_current */
1400 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < device->brightness->count; i++) {
1401 		l = device->brightness->levels[i];
1402 		if (abs(l - level_current) < abs(delta)) {
1403 			delta = l - level_current;
1404 			if (!delta)
1405 				break;
1406 		}
1407 	}
1408 	/* Adjust level_current to closest available level */
1409 	level_current += delta;
1410 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < device->brightness->count; i++) {
1411 		l = device->brightness->levels[i];
1412 		if (l < min)
1413 			min = l;
1414 		if (l > max)
1415 			max = l;
1416 		if (l < min_above && l > level_current)
1417 			min_above = l;
1418 		if (l > max_below && l < level_current)
1419 			max_below = l;
1420 	}
1421 
1422 	switch (event) {
1423 	case ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS:
1424 		return (level_current < max) ? min_above : min;
1425 	case ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS:
1426 		return (level_current < max) ? min_above : max;
1427 	case ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS:
1428 		return (level_current > min) ? max_below : min;
1429 	case ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS:
1430 	case ACPI_VIDEO_NOTIFY_DISPLAY_OFF:
1431 		return 0;
1432 	default:
1433 		return level_current;
1434 	}
1435 }
1436 
1437 static void
1438 acpi_video_switch_brightness(struct work_struct *work)
1439 {
1440 	struct acpi_video_device *device = container_of(to_delayed_work(work),
1441 			     struct acpi_video_device, switch_brightness_work);
1442 	unsigned long long level_current, level_next;
1443 	int event = device->switch_brightness_event;
1444 	int result = -EINVAL;
1445 
1446 	/* no warning message if acpi_backlight=vendor or a quirk is used */
1447 	if (!device->backlight)
1448 		return;
1449 
1450 	if (!device->brightness)
1451 		goto out;
1452 
1453 	result = acpi_video_device_lcd_get_level_current(device,
1454 							 &level_current,
1455 							 false);
1456 	if (result)
1457 		goto out;
1458 
1459 	level_next = acpi_video_get_next_level(device, level_current, event);
1460 
1461 	result = acpi_video_device_lcd_set_level(device, level_next);
1462 
1463 	if (!result)
1464 		backlight_force_update(device->backlight,
1465 				       BACKLIGHT_UPDATE_HOTKEY);
1466 
1467 out:
1468 	if (result)
1469 		acpi_handle_info(device->dev->handle,
1470 				 "Failed to switch brightness\n");
1471 }
1472 
1473 int acpi_video_get_edid(struct acpi_device *device, int type, int device_id,
1474 			void **edid)
1475 {
1476 	struct acpi_video_bus *video;
1477 	struct acpi_video_device *video_device;
1478 	union acpi_object *buffer = NULL;
1479 	acpi_status status;
1480 	int i, length;
1481 
1482 	if (!device || !acpi_driver_data(device))
1483 		return -EINVAL;
1484 
1485 	video = acpi_driver_data(device);
1486 
1487 	for (i = 0; i < video->attached_count; i++) {
1488 		video_device = video->attached_array[i].bind_info;
1489 		length = 256;
1490 
1491 		if (!video_device)
1492 			continue;
1493 
1494 		if (!video_device->cap._DDC)
1495 			continue;
1496 
1497 		if (type) {
1498 			switch (type) {
1499 			case ACPI_VIDEO_DISPLAY_CRT:
1500 				if (!video_device->flags.crt)
1501 					continue;
1502 				break;
1503 			case ACPI_VIDEO_DISPLAY_TV:
1504 				if (!video_device->flags.tvout)
1505 					continue;
1506 				break;
1507 			case ACPI_VIDEO_DISPLAY_DVI:
1508 				if (!video_device->flags.dvi)
1509 					continue;
1510 				break;
1511 			case ACPI_VIDEO_DISPLAY_LCD:
1512 				if (!video_device->flags.lcd)
1513 					continue;
1514 				break;
1515 			}
1516 		} else if (video_device->device_id != device_id) {
1517 			continue;
1518 		}
1519 
1520 		status = acpi_video_device_EDID(video_device, &buffer, length);
1521 
1522 		if (ACPI_FAILURE(status) || !buffer ||
1523 		    buffer->type != ACPI_TYPE_BUFFER) {
1524 			length = 128;
1525 			status = acpi_video_device_EDID(video_device, &buffer,
1526 							length);
1527 			if (ACPI_FAILURE(status) || !buffer ||
1528 			    buffer->type != ACPI_TYPE_BUFFER) {
1529 				continue;
1530 			}
1531 		}
1532 
1533 		*edid = buffer->buffer.pointer;
1534 		return length;
1535 	}
1536 
1537 	return -ENODEV;
1538 }
1539 EXPORT_SYMBOL(acpi_video_get_edid);
1540 
1541 static int
1542 acpi_video_bus_get_devices(struct acpi_video_bus *video,
1543 			   struct acpi_device *device)
1544 {
1545 	int status = 0;
1546 	struct acpi_device *dev;
1547 
1548 	/*
1549 	 * There are systems where video module known to work fine regardless
1550 	 * of broken _DOD and ignoring returned value here doesn't cause
1551 	 * any issues later.
1552 	 */
1553 	acpi_video_device_enumerate(video);
1554 
1555 	list_for_each_entry(dev, &device->children, node) {
1556 
1557 		status = acpi_video_bus_get_one_device(dev, video);
1558 		if (status) {
1559 			dev_err(&dev->dev, "Can't attach device\n");
1560 			break;
1561 		}
1562 		video->child_count++;
1563 	}
1564 	return status;
1565 }
1566 
1567 /* acpi_video interface */
1568 
1569 /*
1570  * Win8 requires setting bit2 of _DOS to let firmware know it shouldn't
1571  * perform any automatic brightness change on receiving a notification.
1572  */
1573 static int acpi_video_bus_start_devices(struct acpi_video_bus *video)
1574 {
1575 	return acpi_video_bus_DOS(video, 0,
1576 				  acpi_osi_is_win8() ? 1 : 0);
1577 }
1578 
1579 static int acpi_video_bus_stop_devices(struct acpi_video_bus *video)
1580 {
1581 	return acpi_video_bus_DOS(video, 0,
1582 				  acpi_osi_is_win8() ? 0 : 1);
1583 }
1584 
1585 static void acpi_video_bus_notify(struct acpi_device *device, u32 event)
1586 {
1587 	struct acpi_video_bus *video = acpi_driver_data(device);
1588 	struct input_dev *input;
1589 	int keycode = 0;
1590 
1591 	if (!video || !video->input)
1592 		return;
1593 
1594 	input = video->input;
1595 
1596 	switch (event) {
1597 	case ACPI_VIDEO_NOTIFY_SWITCH:	/* User requested a switch,
1598 					 * most likely via hotkey. */
1599 		keycode = KEY_SWITCHVIDEOMODE;
1600 		break;
1601 
1602 	case ACPI_VIDEO_NOTIFY_PROBE:	/* User plugged in or removed a video
1603 					 * connector. */
1604 		acpi_video_device_enumerate(video);
1605 		acpi_video_device_rebind(video);
1606 		keycode = KEY_SWITCHVIDEOMODE;
1607 		break;
1608 
1609 	case ACPI_VIDEO_NOTIFY_CYCLE:	/* Cycle Display output hotkey pressed. */
1610 		keycode = KEY_SWITCHVIDEOMODE;
1611 		break;
1612 	case ACPI_VIDEO_NOTIFY_NEXT_OUTPUT:	/* Next Display output hotkey pressed. */
1613 		keycode = KEY_VIDEO_NEXT;
1614 		break;
1615 	case ACPI_VIDEO_NOTIFY_PREV_OUTPUT:	/* previous Display output hotkey pressed. */
1616 		keycode = KEY_VIDEO_PREV;
1617 		break;
1618 
1619 	default:
1620 		acpi_handle_debug(device->handle, "Unsupported event [0x%x]\n",
1621 				  event);
1622 		break;
1623 	}
1624 
1625 	if (acpi_notifier_call_chain(device, event, 0))
1626 		/* Something vetoed the keypress. */
1627 		keycode = 0;
1628 
1629 	if (keycode && (report_key_events & REPORT_OUTPUT_KEY_EVENTS)) {
1630 		input_report_key(input, keycode, 1);
1631 		input_sync(input);
1632 		input_report_key(input, keycode, 0);
1633 		input_sync(input);
1634 	}
1635 }
1636 
1637 static void brightness_switch_event(struct acpi_video_device *video_device,
1638 				    u32 event)
1639 {
1640 	if (!brightness_switch_enabled)
1641 		return;
1642 
1643 	video_device->switch_brightness_event = event;
1644 	schedule_delayed_work(&video_device->switch_brightness_work, HZ / 10);
1645 }
1646 
1647 static void acpi_video_device_notify(acpi_handle handle, u32 event, void *data)
1648 {
1649 	struct acpi_video_device *video_device = data;
1650 	struct acpi_device *device = NULL;
1651 	struct acpi_video_bus *bus;
1652 	struct input_dev *input;
1653 	int keycode = 0;
1654 
1655 	if (!video_device)
1656 		return;
1657 
1658 	device = video_device->dev;
1659 	bus = video_device->video;
1660 	input = bus->input;
1661 
1662 	if (hw_changes_brightness > 0) {
1663 		if (video_device->backlight)
1664 			backlight_force_update(video_device->backlight,
1665 					       BACKLIGHT_UPDATE_HOTKEY);
1666 		acpi_notifier_call_chain(device, event, 0);
1667 		return;
1668 	}
1669 
1670 	switch (event) {
1671 	case ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS:	/* Cycle brightness */
1672 		brightness_switch_event(video_device, event);
1673 		keycode = KEY_BRIGHTNESS_CYCLE;
1674 		break;
1675 	case ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS:	/* Increase brightness */
1676 		brightness_switch_event(video_device, event);
1677 		keycode = KEY_BRIGHTNESSUP;
1678 		break;
1679 	case ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS:	/* Decrease brightness */
1680 		brightness_switch_event(video_device, event);
1681 		keycode = KEY_BRIGHTNESSDOWN;
1682 		break;
1683 	case ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS:	/* zero brightness */
1684 		brightness_switch_event(video_device, event);
1685 		keycode = KEY_BRIGHTNESS_ZERO;
1686 		break;
1687 	case ACPI_VIDEO_NOTIFY_DISPLAY_OFF:	/* display device off */
1688 		brightness_switch_event(video_device, event);
1689 		keycode = KEY_DISPLAY_OFF;
1690 		break;
1691 	default:
1692 		acpi_handle_debug(handle, "Unsupported event [0x%x]\n", event);
1693 		break;
1694 	}
1695 
1696 	acpi_notifier_call_chain(device, event, 0);
1697 
1698 	if (keycode && (report_key_events & REPORT_BRIGHTNESS_KEY_EVENTS)) {
1699 		input_report_key(input, keycode, 1);
1700 		input_sync(input);
1701 		input_report_key(input, keycode, 0);
1702 		input_sync(input);
1703 	}
1704 }
1705 
1706 static int acpi_video_resume(struct notifier_block *nb,
1707 				unsigned long val, void *ign)
1708 {
1709 	struct acpi_video_bus *video;
1710 	struct acpi_video_device *video_device;
1711 	int i;
1712 
1713 	switch (val) {
1714 	case PM_POST_HIBERNATION:
1715 	case PM_POST_SUSPEND:
1716 	case PM_POST_RESTORE:
1717 		video = container_of(nb, struct acpi_video_bus, pm_nb);
1718 
1719 		dev_info(&video->device->dev, "Restoring backlight state\n");
1720 
1721 		for (i = 0; i < video->attached_count; i++) {
1722 			video_device = video->attached_array[i].bind_info;
1723 			if (video_device && video_device->brightness)
1724 				acpi_video_device_lcd_set_level(video_device,
1725 						video_device->brightness->curr);
1726 		}
1727 
1728 		return NOTIFY_OK;
1729 	}
1730 	return NOTIFY_DONE;
1731 }
1732 
1733 static acpi_status
1734 acpi_video_bus_match(acpi_handle handle, u32 level, void *context,
1735 			void **return_value)
1736 {
1737 	struct acpi_device *device = context;
1738 	struct acpi_device *sibling;
1739 
1740 	if (handle == device->handle)
1741 		return AE_CTRL_TERMINATE;
1742 
1743 	sibling = acpi_fetch_acpi_dev(handle);
1744 	if (!sibling)
1745 		return AE_OK;
1746 
1747 	if (!strcmp(acpi_device_name(sibling), ACPI_VIDEO_BUS_NAME))
1748 			return AE_ALREADY_EXISTS;
1749 
1750 	return AE_OK;
1751 }
1752 
1753 static void acpi_video_dev_register_backlight(struct acpi_video_device *device)
1754 {
1755 	struct backlight_properties props;
1756 	struct pci_dev *pdev;
1757 	acpi_handle acpi_parent;
1758 	struct device *parent = NULL;
1759 	int result;
1760 	static int count;
1761 	char *name;
1762 
1763 	result = acpi_video_init_brightness(device);
1764 	if (result)
1765 		return;
1766 
1767 	if (disable_backlight_sysfs_if > 0)
1768 		return;
1769 
1770 	name = kasprintf(GFP_KERNEL, "acpi_video%d", count);
1771 	if (!name)
1772 		return;
1773 	count++;
1774 
1775 	acpi_get_parent(device->dev->handle, &acpi_parent);
1776 
1777 	pdev = acpi_get_pci_dev(acpi_parent);
1778 	if (pdev) {
1779 		parent = &pdev->dev;
1780 		pci_dev_put(pdev);
1781 	}
1782 
1783 	memset(&props, 0, sizeof(struct backlight_properties));
1784 	props.type = BACKLIGHT_FIRMWARE;
1785 	props.max_brightness =
1786 		device->brightness->count - ACPI_VIDEO_FIRST_LEVEL - 1;
1787 	device->backlight = backlight_device_register(name,
1788 						      parent,
1789 						      device,
1790 						      &acpi_backlight_ops,
1791 						      &props);
1792 	kfree(name);
1793 	if (IS_ERR(device->backlight)) {
1794 		device->backlight = NULL;
1795 		return;
1796 	}
1797 
1798 	/*
1799 	 * Save current brightness level in case we have to restore it
1800 	 * before acpi_video_device_lcd_set_level() is called next time.
1801 	 */
1802 	device->backlight->props.brightness =
1803 			acpi_video_get_brightness(device->backlight);
1804 
1805 	device->cooling_dev = thermal_cooling_device_register("LCD",
1806 				device->dev, &video_cooling_ops);
1807 	if (IS_ERR(device->cooling_dev)) {
1808 		/*
1809 		 * Set cooling_dev to NULL so we don't crash trying to free it.
1810 		 * Also, why the hell we are returning early and not attempt to
1811 		 * register video output if cooling device registration failed?
1812 		 * -- dtor
1813 		 */
1814 		device->cooling_dev = NULL;
1815 		return;
1816 	}
1817 
1818 	dev_info(&device->dev->dev, "registered as cooling_device%d\n",
1819 		 device->cooling_dev->id);
1820 	result = sysfs_create_link(&device->dev->dev.kobj,
1821 			&device->cooling_dev->device.kobj,
1822 			"thermal_cooling");
1823 	if (result)
1824 		pr_info("sysfs link creation failed\n");
1825 
1826 	result = sysfs_create_link(&device->cooling_dev->device.kobj,
1827 			&device->dev->dev.kobj, "device");
1828 	if (result)
1829 		pr_info("Reverse sysfs link creation failed\n");
1830 }
1831 
1832 static void acpi_video_run_bcl_for_osi(struct acpi_video_bus *video)
1833 {
1834 	struct acpi_video_device *dev;
1835 	union acpi_object *levels;
1836 
1837 	mutex_lock(&video->device_list_lock);
1838 	list_for_each_entry(dev, &video->video_device_list, entry) {
1839 		if (!acpi_video_device_lcd_query_levels(dev->dev->handle, &levels))
1840 			kfree(levels);
1841 	}
1842 	mutex_unlock(&video->device_list_lock);
1843 }
1844 
1845 static bool acpi_video_should_register_backlight(struct acpi_video_device *dev)
1846 {
1847 	/*
1848 	 * Do not create backlight device for video output
1849 	 * device that is not in the enumerated list.
1850 	 */
1851 	if (!acpi_video_device_in_dod(dev)) {
1852 		dev_dbg(&dev->dev->dev, "not in _DOD list, ignore\n");
1853 		return false;
1854 	}
1855 
1856 	if (only_lcd)
1857 		return dev->flags.lcd;
1858 	return true;
1859 }
1860 
1861 static int acpi_video_bus_register_backlight(struct acpi_video_bus *video)
1862 {
1863 	struct acpi_video_device *dev;
1864 
1865 	if (video->backlight_registered)
1866 		return 0;
1867 
1868 	acpi_video_run_bcl_for_osi(video);
1869 
1870 	if (acpi_video_get_backlight_type() != acpi_backlight_video)
1871 		return 0;
1872 
1873 	mutex_lock(&video->device_list_lock);
1874 	list_for_each_entry(dev, &video->video_device_list, entry) {
1875 		if (acpi_video_should_register_backlight(dev))
1876 			acpi_video_dev_register_backlight(dev);
1877 	}
1878 	mutex_unlock(&video->device_list_lock);
1879 
1880 	video->backlight_registered = true;
1881 
1882 	video->pm_nb.notifier_call = acpi_video_resume;
1883 	video->pm_nb.priority = 0;
1884 	return register_pm_notifier(&video->pm_nb);
1885 }
1886 
1887 static void acpi_video_dev_unregister_backlight(struct acpi_video_device *device)
1888 {
1889 	if (device->backlight) {
1890 		backlight_device_unregister(device->backlight);
1891 		device->backlight = NULL;
1892 	}
1893 	if (device->brightness) {
1894 		kfree(device->brightness->levels);
1895 		kfree(device->brightness);
1896 		device->brightness = NULL;
1897 	}
1898 	if (device->cooling_dev) {
1899 		sysfs_remove_link(&device->dev->dev.kobj, "thermal_cooling");
1900 		sysfs_remove_link(&device->cooling_dev->device.kobj, "device");
1901 		thermal_cooling_device_unregister(device->cooling_dev);
1902 		device->cooling_dev = NULL;
1903 	}
1904 }
1905 
1906 static int acpi_video_bus_unregister_backlight(struct acpi_video_bus *video)
1907 {
1908 	struct acpi_video_device *dev;
1909 	int error;
1910 
1911 	if (!video->backlight_registered)
1912 		return 0;
1913 
1914 	error = unregister_pm_notifier(&video->pm_nb);
1915 
1916 	mutex_lock(&video->device_list_lock);
1917 	list_for_each_entry(dev, &video->video_device_list, entry)
1918 		acpi_video_dev_unregister_backlight(dev);
1919 	mutex_unlock(&video->device_list_lock);
1920 
1921 	video->backlight_registered = false;
1922 
1923 	return error;
1924 }
1925 
1926 static void acpi_video_dev_add_notify_handler(struct acpi_video_device *device)
1927 {
1928 	acpi_status status;
1929 	struct acpi_device *adev = device->dev;
1930 
1931 	status = acpi_install_notify_handler(adev->handle, ACPI_DEVICE_NOTIFY,
1932 					     acpi_video_device_notify, device);
1933 	if (ACPI_FAILURE(status))
1934 		dev_err(&adev->dev, "Error installing notify handler\n");
1935 	else
1936 		device->flags.notify = 1;
1937 }
1938 
1939 static int acpi_video_bus_add_notify_handler(struct acpi_video_bus *video)
1940 {
1941 	struct input_dev *input;
1942 	struct acpi_video_device *dev;
1943 	int error;
1944 
1945 	video->input = input = input_allocate_device();
1946 	if (!input) {
1947 		error = -ENOMEM;
1948 		goto out;
1949 	}
1950 
1951 	error = acpi_video_bus_start_devices(video);
1952 	if (error)
1953 		goto err_free_input;
1954 
1955 	snprintf(video->phys, sizeof(video->phys),
1956 			"%s/video/input0", acpi_device_hid(video->device));
1957 
1958 	input->name = acpi_device_name(video->device);
1959 	input->phys = video->phys;
1960 	input->id.bustype = BUS_HOST;
1961 	input->id.product = 0x06;
1962 	input->dev.parent = &video->device->dev;
1963 	input->evbit[0] = BIT(EV_KEY);
1964 	set_bit(KEY_SWITCHVIDEOMODE, input->keybit);
1965 	set_bit(KEY_VIDEO_NEXT, input->keybit);
1966 	set_bit(KEY_VIDEO_PREV, input->keybit);
1967 	set_bit(KEY_BRIGHTNESS_CYCLE, input->keybit);
1968 	set_bit(KEY_BRIGHTNESSUP, input->keybit);
1969 	set_bit(KEY_BRIGHTNESSDOWN, input->keybit);
1970 	set_bit(KEY_BRIGHTNESS_ZERO, input->keybit);
1971 	set_bit(KEY_DISPLAY_OFF, input->keybit);
1972 
1973 	error = input_register_device(input);
1974 	if (error)
1975 		goto err_stop_dev;
1976 
1977 	mutex_lock(&video->device_list_lock);
1978 	list_for_each_entry(dev, &video->video_device_list, entry)
1979 		acpi_video_dev_add_notify_handler(dev);
1980 	mutex_unlock(&video->device_list_lock);
1981 
1982 	return 0;
1983 
1984 err_stop_dev:
1985 	acpi_video_bus_stop_devices(video);
1986 err_free_input:
1987 	input_free_device(input);
1988 	video->input = NULL;
1989 out:
1990 	return error;
1991 }
1992 
1993 static void acpi_video_dev_remove_notify_handler(struct acpi_video_device *dev)
1994 {
1995 	if (dev->flags.notify) {
1996 		acpi_remove_notify_handler(dev->dev->handle, ACPI_DEVICE_NOTIFY,
1997 					   acpi_video_device_notify);
1998 		dev->flags.notify = 0;
1999 	}
2000 }
2001 
2002 static void acpi_video_bus_remove_notify_handler(struct acpi_video_bus *video)
2003 {
2004 	struct acpi_video_device *dev;
2005 
2006 	mutex_lock(&video->device_list_lock);
2007 	list_for_each_entry(dev, &video->video_device_list, entry)
2008 		acpi_video_dev_remove_notify_handler(dev);
2009 	mutex_unlock(&video->device_list_lock);
2010 
2011 	acpi_video_bus_stop_devices(video);
2012 	input_unregister_device(video->input);
2013 	video->input = NULL;
2014 }
2015 
2016 static int acpi_video_bus_put_devices(struct acpi_video_bus *video)
2017 {
2018 	struct acpi_video_device *dev, *next;
2019 
2020 	mutex_lock(&video->device_list_lock);
2021 	list_for_each_entry_safe(dev, next, &video->video_device_list, entry) {
2022 		list_del(&dev->entry);
2023 		kfree(dev);
2024 	}
2025 	mutex_unlock(&video->device_list_lock);
2026 
2027 	return 0;
2028 }
2029 
2030 static int instance;
2031 
2032 static int acpi_video_bus_add(struct acpi_device *device)
2033 {
2034 	struct acpi_video_bus *video;
2035 	int error;
2036 	acpi_status status;
2037 
2038 	status = acpi_walk_namespace(ACPI_TYPE_DEVICE,
2039 				device->parent->handle, 1,
2040 				acpi_video_bus_match, NULL,
2041 				device, NULL);
2042 	if (status == AE_ALREADY_EXISTS) {
2043 		pr_info(FW_BUG
2044 			"Duplicate ACPI video bus devices for the"
2045 			" same VGA controller, please try module "
2046 			"parameter \"video.allow_duplicates=1\""
2047 			"if the current driver doesn't work.\n");
2048 		if (!allow_duplicates)
2049 			return -ENODEV;
2050 	}
2051 
2052 	video = kzalloc(sizeof(struct acpi_video_bus), GFP_KERNEL);
2053 	if (!video)
2054 		return -ENOMEM;
2055 
2056 	/* a hack to fix the duplicate name "VID" problem on T61 */
2057 	if (!strcmp(device->pnp.bus_id, "VID")) {
2058 		if (instance)
2059 			device->pnp.bus_id[3] = '0' + instance;
2060 		instance++;
2061 	}
2062 	/* a hack to fix the duplicate name "VGA" problem on Pa 3553 */
2063 	if (!strcmp(device->pnp.bus_id, "VGA")) {
2064 		if (instance)
2065 			device->pnp.bus_id[3] = '0' + instance;
2066 		instance++;
2067 	}
2068 
2069 	video->device = device;
2070 	strcpy(acpi_device_name(device), ACPI_VIDEO_BUS_NAME);
2071 	strcpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
2072 	device->driver_data = video;
2073 
2074 	acpi_video_bus_find_cap(video);
2075 	error = acpi_video_bus_check(video);
2076 	if (error)
2077 		goto err_free_video;
2078 
2079 	mutex_init(&video->device_list_lock);
2080 	INIT_LIST_HEAD(&video->video_device_list);
2081 
2082 	error = acpi_video_bus_get_devices(video, device);
2083 	if (error)
2084 		goto err_put_video;
2085 
2086 	pr_info("%s [%s] (multi-head: %s  rom: %s  post: %s)\n",
2087 	       ACPI_VIDEO_DEVICE_NAME, acpi_device_bid(device),
2088 	       video->flags.multihead ? "yes" : "no",
2089 	       video->flags.rom ? "yes" : "no",
2090 	       video->flags.post ? "yes" : "no");
2091 	mutex_lock(&video_list_lock);
2092 	list_add_tail(&video->entry, &video_bus_head);
2093 	mutex_unlock(&video_list_lock);
2094 
2095 	acpi_video_bus_register_backlight(video);
2096 	acpi_video_bus_add_notify_handler(video);
2097 
2098 	return 0;
2099 
2100 err_put_video:
2101 	acpi_video_bus_put_devices(video);
2102 	kfree(video->attached_array);
2103 err_free_video:
2104 	kfree(video);
2105 	device->driver_data = NULL;
2106 
2107 	return error;
2108 }
2109 
2110 static int acpi_video_bus_remove(struct acpi_device *device)
2111 {
2112 	struct acpi_video_bus *video = NULL;
2113 
2114 
2115 	if (!device || !acpi_driver_data(device))
2116 		return -EINVAL;
2117 
2118 	video = acpi_driver_data(device);
2119 
2120 	acpi_video_bus_remove_notify_handler(video);
2121 	acpi_video_bus_unregister_backlight(video);
2122 	acpi_video_bus_put_devices(video);
2123 
2124 	mutex_lock(&video_list_lock);
2125 	list_del(&video->entry);
2126 	mutex_unlock(&video_list_lock);
2127 
2128 	kfree(video->attached_array);
2129 	kfree(video);
2130 
2131 	return 0;
2132 }
2133 
2134 static int __init is_i740(struct pci_dev *dev)
2135 {
2136 	if (dev->device == 0x00D1)
2137 		return 1;
2138 	if (dev->device == 0x7000)
2139 		return 1;
2140 	return 0;
2141 }
2142 
2143 static int __init intel_opregion_present(void)
2144 {
2145 	int opregion = 0;
2146 	struct pci_dev *dev = NULL;
2147 	u32 address;
2148 
2149 	for_each_pci_dev(dev) {
2150 		if ((dev->class >> 8) != PCI_CLASS_DISPLAY_VGA)
2151 			continue;
2152 		if (dev->vendor != PCI_VENDOR_ID_INTEL)
2153 			continue;
2154 		/* We don't want to poke around undefined i740 registers */
2155 		if (is_i740(dev))
2156 			continue;
2157 		pci_read_config_dword(dev, 0xfc, &address);
2158 		if (!address)
2159 			continue;
2160 		opregion = 1;
2161 	}
2162 	return opregion;
2163 }
2164 
2165 /* Check if the chassis-type indicates there is no builtin LCD panel */
2166 static bool dmi_is_desktop(void)
2167 {
2168 	const char *chassis_type;
2169 	unsigned long type;
2170 
2171 	chassis_type = dmi_get_system_info(DMI_CHASSIS_TYPE);
2172 	if (!chassis_type)
2173 		return false;
2174 
2175 	if (kstrtoul(chassis_type, 10, &type) != 0)
2176 		return false;
2177 
2178 	switch (type) {
2179 	case 0x03: /* Desktop */
2180 	case 0x04: /* Low Profile Desktop */
2181 	case 0x05: /* Pizza Box */
2182 	case 0x06: /* Mini Tower */
2183 	case 0x07: /* Tower */
2184 	case 0x10: /* Lunch Box */
2185 	case 0x11: /* Main Server Chassis */
2186 		return true;
2187 	}
2188 
2189 	return false;
2190 }
2191 
2192 /*
2193  * We're seeing a lot of bogus backlight interfaces on newer machines
2194  * without a LCD such as desktops, servers and HDMI sticks. Checking the
2195  * lcd flag fixes this, enable this by default on any machines which are:
2196  * 1.  Win8 ready (where we also prefer the native backlight driver, so
2197  *     normally the acpi_video code should not register there anyways); *and*
2198  * 2.1 Report a desktop/server DMI chassis-type, or
2199  * 2.2 Are an ACPI-reduced-hardware platform (and thus won't use the EC for
2200        backlight control)
2201  */
2202 static bool should_check_lcd_flag(void)
2203 {
2204 	if (!acpi_osi_is_win8())
2205 		return false;
2206 
2207 	if (dmi_is_desktop())
2208 		return true;
2209 
2210 	if (acpi_reduced_hardware())
2211 		return true;
2212 
2213 	return false;
2214 }
2215 
2216 int acpi_video_register(void)
2217 {
2218 	int ret = 0;
2219 
2220 	mutex_lock(&register_count_mutex);
2221 	if (register_count) {
2222 		/*
2223 		 * if the function of acpi_video_register is already called,
2224 		 * don't register the acpi_video_bus again and return no error.
2225 		 */
2226 		goto leave;
2227 	}
2228 
2229 	if (only_lcd == -1)
2230 		only_lcd = should_check_lcd_flag();
2231 
2232 	dmi_check_system(video_dmi_table);
2233 
2234 	ret = acpi_bus_register_driver(&acpi_video_bus);
2235 	if (ret)
2236 		goto leave;
2237 
2238 	/*
2239 	 * When the acpi_video_bus is loaded successfully, increase
2240 	 * the counter reference.
2241 	 */
2242 	register_count = 1;
2243 
2244 leave:
2245 	mutex_unlock(&register_count_mutex);
2246 	return ret;
2247 }
2248 EXPORT_SYMBOL(acpi_video_register);
2249 
2250 void acpi_video_unregister(void)
2251 {
2252 	mutex_lock(&register_count_mutex);
2253 	if (register_count) {
2254 		acpi_bus_unregister_driver(&acpi_video_bus);
2255 		register_count = 0;
2256 		has_backlight = false;
2257 	}
2258 	mutex_unlock(&register_count_mutex);
2259 }
2260 EXPORT_SYMBOL(acpi_video_unregister);
2261 
2262 void acpi_video_unregister_backlight(void)
2263 {
2264 	struct acpi_video_bus *video;
2265 
2266 	mutex_lock(&register_count_mutex);
2267 	if (register_count) {
2268 		mutex_lock(&video_list_lock);
2269 		list_for_each_entry(video, &video_bus_head, entry)
2270 			acpi_video_bus_unregister_backlight(video);
2271 		mutex_unlock(&video_list_lock);
2272 	}
2273 	mutex_unlock(&register_count_mutex);
2274 }
2275 
2276 bool acpi_video_handles_brightness_key_presses(void)
2277 {
2278 	return has_backlight &&
2279 	       (report_key_events & REPORT_BRIGHTNESS_KEY_EVENTS);
2280 }
2281 EXPORT_SYMBOL(acpi_video_handles_brightness_key_presses);
2282 
2283 /*
2284  * This is kind of nasty. Hardware using Intel chipsets may require
2285  * the video opregion code to be run first in order to initialise
2286  * state before any ACPI video calls are made. To handle this we defer
2287  * registration of the video class until the opregion code has run.
2288  */
2289 
2290 static int __init acpi_video_init(void)
2291 {
2292 	/*
2293 	 * Let the module load even if ACPI is disabled (e.g. due to
2294 	 * a broken BIOS) so that i915.ko can still be loaded on such
2295 	 * old systems without an AcpiOpRegion.
2296 	 *
2297 	 * acpi_video_register() will report -ENODEV later as well due
2298 	 * to acpi_disabled when i915.ko tries to register itself afterwards.
2299 	 */
2300 	if (acpi_disabled)
2301 		return 0;
2302 
2303 	if (intel_opregion_present())
2304 		return 0;
2305 
2306 	return acpi_video_register();
2307 }
2308 
2309 static void __exit acpi_video_exit(void)
2310 {
2311 	acpi_video_detect_exit();
2312 	acpi_video_unregister();
2313 }
2314 
2315 module_init(acpi_video_init);
2316 module_exit(acpi_video_exit);
2317